1. Field of the Invention
The present invention relates to an ink container for containing recording liquid such as liquid ink or ink in a solid state but liquefied at least at the time of use and applicable to various kinds of recording equipment. More particularly, the present invention relates to an atmosphere communicating construction for making an ink container communicate with the atmosphere or the outside air, with an ink jet recording head for recording by means of droplets and a tank for supplying recording liquid to the recording head which are held as a section, and to what is effectively applicable to such a recording head.
2. Related Background Art
In an ink cartridge incorporating a recording head and an ink container for supplying ink to a recording head cartridge and a recording head which are reciprocally moved on a carriage, the recording head and the ink container have been known to contain a porous material: the former for holding the ink supplied and the latter for containing waste ink. These are normally provided with an atmosphere communicating port for equalizing the atmospheric pressure and the internal pressure of a tank, though there still exist problems of ink leakage and ink rocking. Although attempts have been made to prevent ink from leaking from the port by providing the port with a porous film, such a film is expensive and the provision of the film involves a great deal of not only skill but also cost. Although it may be considered feasible to prevent ink leakage by providing a large-sized atmosphere communicating port, there arises another problem in that the apparatus tends to become large in size.
In some of the high-speed printing machines for full-line printing using large-sized recording heads, there are installed large-sized tanks whose openings to the atmosphere are positively provided with automatic switch valves. However, the provision of such an automatic switch valve tends to make the machine costly.
Unlike an ordinary recording cartridge whose tank simply has an atmosphere communicating port, a tank containing a porous material basically allows recording liquid to be held in the porous material, thus preventing the recording liquid from leaking out of the atmosphere communicating port and a nozzle in normal operation. In case a shock resulting from falling or vibration is applied to the recording cartridge, the recording liquid may scatter in the air as it cannot be held in the porous material any longer. If the droplets thus scattered stick to the atmosphere communicating port, the recording liquid may spring out of the cartridge through the atmosphere communicating port and soil the outer wall.